The invention relates generally to passenger protection devices for vehicles, and more specifically to a rollover protection device.
DE 43 42 400 A1 discloses one type of rollover protection device including a cassette housing made from aluminum and having side walls which are interconnected via a guiding body formed as an aluminum form part. The cassette housing has a bottom plate which grips around the lower ends of the rollover bar which is formed as a U-shaped tube bracket. The side walls as well are interconnected by a rear wall made from aluminum. The guiding body guides the U-legs of the rollover bar via slide bushings made from plastics. The U-legs of the rollover bar additionally are guided on plastic standpipes extending upwardly from the bottom plate. As a consequence, the cassette housing includes a compound structure of aluminum and plastic. Since the rear wall interconnects the side walls exclusively in the lower part of the cassette housing while the guiding body extends exclusively in the upper part of the cassette housing and between the side walls, the guiding body has to serve as a main load carrying element. The achievable crash performance in this type of device is correlated to the weight of the entire structural unit.
U-shaped cassette housings for receiving U-shaped tubular rollover bars are disclosed in, for example, U.S. Pat. No. 5,626,361 A (DE 43 14 538 A), EP 1 084 914 A, EP 1 038 735 A, and EP 1 028 050 A. These cassette housings are open at one broader side. Relatively small force transmitting areas are formed between the cassette housing having the U-cross-section and one open side and the vehicle body which force transmitting areas will be loaded by locally concentrated stress in a crash case.
A shell construction of rollover bars made from fibre reinforced compound plastic-is disclosed in, for example, DE 20 10 30 01 U. These rollover bars are directly guided between a profiled bulkhead of the vehicle body and a lateral beam made of fibre reinforced compound plastic material.
It would be desirable to provide a rollover protection device having a fair cost structure, extremely low weight and nevertheless an excellent crash performance.